Little Snitch 4.1 - Alerts you about outgoing network connections.

Track background activity
As soon as your computer connects to the Internet, applications often have permission to send any information wherever they need to. Little Snitch takes note of this activity and allows you to decide for yourself what happens with this data.

Control your network
Choose to allow or deny connections, or define a rule how to handle similar, future connection attempts. Little Snitch runs inconspicuously in the background and it can even detect network-related activity of viruses, trojans, and other malware.

Version 4.1: Note: Version 4 is a paid upgrade from previous versions.

Improvements:

Improved display of inactive rules in Little Snitch Configuration. If a rule is inactive for whatever reason - either if it’s not enabled, if it’s part of a profile that’s currently not activated, if it’s in a rule group that’s currently not activated, or if the entire network filter is turned off - the rule is now consistently displayed with a gray text color.

Focus Mode: Little Snitch Configuration has a new mode that allows you to focus on a specific subset of rules. Selecting one or more rules and then choosing Focus on Selected Rules or Focus on Rules Affecting Selection from the View menu will focus on just the rules you want to see, while leaving the search field free for further filtering. Focus Mode is also used for revealing matching rules from the connection alert or Network Monitor (e.g. by right-clicking a connection and choosing Show Corresponding Rules).

The rule groups "iCloud Services" and "macOS Services" (previously named "Managed Rules") can now be activated and deactivated using a checkbox next to their name in Little Snitch Configuration’s left sidebar (previously, these checkboxes could be found in the preferences window). This allows you to see what rules these sets contain before activating them.

Profiles can now be activated and deactivated in Little Snitch Configuration’s left sidebar using a checkbox next to the profile.

The special "Code Signature Issue Override Rules" that Little Snitch creates under certain circumstances can now be edited in Little Snitch Configuration just like normal rules. This should make it less confusing to deal with situations where an application is reported to have no valid code signature. See Code signature issues > Special Code Signature Issue Override Rules for more details.

Connection alerts for applications that have an issue with their code signature now include direct links to the relevant section of the online documentation. The relevant chapter Code signature issues has been extended to provide much more details and examples for how Little Snitch behaves when an application without a valid code signature tries to establish a connection.

Added support for the current version of the QUIC protocol. This fixes an issue with connections from Google Chrome, where the connection alert only showed the IP address instead of the hostname under some circumstances.

In addition to checking that an application’s code signature is valid, Little Snitch now also checks the code signing certificate that was used to create the signature. Only certificates that were issued by Apple are currently accepted.